1. FIELD OF THE INVENTION
The present invention relates to a process of preventing scale formation and more particularly to an improved process of preventing scale formation in aqueous solutions by means of acidic phosphoric acid esters of hydroxy alkyl urea compounds, to compositions containing such acidic acid esters of phosphoric acid, to the acidic esters of phosphoric acid as such, and to a process of making same.
2. DESCRIPTION OF THE PRIOR ART
Acidic phosphoric acid esters of amino alcohols or amino polyalcohols have already been used for preventing scale formation in aqueous solutions. Such esters have proved of value as additives to natural salt-containing liquids, to circulating cooling fluids, to boiler fluids, and the like.
The esters, as they have been used heretofore for this purpose, were produced by phosphorylation of amino alcohols with polyphosphoric acids, phosphoric acid, or urea phosphate.
The scale formation preventing effect of the known phosphoric acid esters, however, is not fully satisfactory.